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Date: Thu, 22 Feb 2024 14:08:11 +0800
From: Herbert Xu <herbert@gondor.apana.org.au>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Ard Biesheuvel <ardb+git@google.com>, linux-crypto@vger.kernel.org,
	stable@vger.kernel.org,
	syzbot+f1ceaa1a09ab891e1934@syzkaller.appspotmail.com
Subject: Re: [PATCH] crypto: arm64/neonbs - fix out-of-bounds access on short
 input
Message-ID: <Zdbky1otr93e9a46@gondor.apana.org.au>
References: <20240217161151.3987164-2-ardb+git@google.com>
 <CAMj1kXH+k4Z_iowxp+t=yU4tQFwLYjQxAQ92bga-xeZxE734BA@mail.gmail.com>
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On Thu, Feb 22, 2024 at 12:37:45AM +0100, Ard Biesheuvel wrote:
> On Sat, 17 Feb 2024 at 17:12, Ard Biesheuvel <ardb+git@google.com> wrote:
> >
> > From: Ard Biesheuvel <ardb@kernel.org>
> >
> > The bit-sliced implementation of AES-CTR operates on blocks of 128
> > bytes, and will fall back to the plain NEON version for tail blocks or
> > inputs that are shorter than 128 bytes to begin with.
> >
> > It will call straight into the plain NEON asm helper, which performs all
> > memory accesses in granules of 16 bytes (the size of a NEON register).
> > For this reason, the associated plain NEON glue code will copy inputs
> > shorter than 16 bytes into a temporary buffer, given that this is a rare
> > occurrence and it is not worth the effort to work around this in the asm
> > code.
> >
> > The fallback from the bit-sliced NEON version fails to take this into
> > account, potentially resulting in out-of-bounds accesses. So clone the
> > same workaround, and use a temp buffer for short in/outputs.
> >
> > Cc: <stable@vger.kernel.org>
> > Reported-by: syzbot+f1ceaa1a09ab891e1934@syzkaller.appspotmail.com
> > Tested-by: syzbot+f1ceaa1a09ab891e1934@syzkaller.appspotmail.com
> > Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> 
> Ping?

It's in my queue.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt